Restructure data model: TrackingConfig + TemplateConfig entities

Major model restructuring for clean separation of concerns:

New entities:
- TrackingConfig: What to react to (event types, asset filters,
  periodic/scheduled/memory mode config) - reusable across targets
- TemplateConfig: All ~15 template slots from blueprint (event
  messages, asset formatting, date/location, scheduled messages)
  with full defaults - separate entities per locale

Changed entities:
- AlbumTracker: Simplified to album selection + polling + target_ids
  (removed event_types, template_id, all filter fields)
- NotificationTarget: Extended with tracking_config_id and
  template_config_id FKs (many-to-one, reusable configs)

Removed entities:
- MessageTemplate (replaced by TemplateConfig)
- ScheduledJob (absorbed into TrackingConfig)

Updated services:
- watcher.py: Each target checked against its own tracking_config
  for event filtering before sending notification
- notifier.py: Uses target's template_config to select the right
  template slot based on event type

New API routes:
- /api/tracking-configs/* (CRUD)
- /api/template-configs/* (CRUD + per-slot preview)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/server/src/immich_watcher_server/services/notifier.py

@@ -11,7 +11,7 @@ from jinja2.sandbox import SandboxedEnvironment
 
 from immich_watcher_core.telegram.client import TelegramClient
 
-from ..database.models import MessageTemplate, NotificationTarget
+from ..database.models import NotificationTarget, TemplateConfig
 from ..webhook.client import WebhookClient
 
 _LOGGER = logging.getLogger(__name__)
@@ -33,7 +33,7 @@ def render_template(template_body: str, context: dict[str, Any]) -> str:
 async def send_notification(
     target: NotificationTarget,
     event_data: dict[str, Any],
-    template: MessageTemplate | None = None,
+    template_config: TemplateConfig | None = None,
     use_ai_caption: bool = False,
 ) -> dict[str, Any]:
     """Send a notification to a target using event data.
@@ -41,7 +41,7 @@ async def send_notification(
     Args:
         target: Notification destination (telegram or webhook)
         event_data: Album change event data (album_name, added_count, etc.)
-        template: Optional message template (uses default if None)
+        template_config: Optional template config with per-event templates
         use_ai_caption: If True, generate caption with Claude AI instead of template
     """
     message = None
@@ -54,7 +54,18 @@ async def send_notification(
 
     # Fall back to template rendering
     if message is None:
-        template_body = template.body if template else DEFAULT_TEMPLATE
+        template_body = DEFAULT_TEMPLATE
+        if template_config:
+            # Select the right template slot based on event type
+            change_type = event_data.get("change_type", "")
+            slot_map = {
+                "assets_added": "message_assets_added",
+                "assets_removed": "message_assets_removed",
+                "album_renamed": "message_album_renamed",
+                "album_deleted": "message_album_deleted",
+            }
+            slot = slot_map.get(change_type, "message_assets_added")
+            template_body = getattr(template_config, slot, DEFAULT_TEMPLATE) or DEFAULT_TEMPLATE
         try:
             message = render_template(template_body, event_data)
         except jinja2.TemplateError as e: